From 5633b3a20c0662a804ceeefb534ec2417f73d12e Mon Sep 17 00:00:00 2001
From: Olivier Galibert <galibert@pobox.com>
Date: Thu, 4 Feb 2021 19:28:13 +0100
Subject: [PATCH] 2gs: Better floppy interaction

---
 src/devices/imagedev/floppy.cpp | 35 +++++++++++++++++++++++----------
 src/devices/machine/iwm.cpp     |  7 ++-----
 2 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/src/devices/imagedev/floppy.cpp b/src/devices/imagedev/floppy.cpp
index 65d3691b8fd..85841bcfdd9 100644
--- a/src/devices/imagedev/floppy.cpp
+++ b/src/devices/imagedev/floppy.cpp
@@ -192,7 +192,7 @@ floppy_image_device::floppy_image_device(const machine_config &mconfig, device_t
 		motor_always_on(false),
 		dskchg_writable(false),
 		has_trk00_sensor(true),
-		dir(0), stp(0), wtg(0), mon(0), ss(0), ds(-1), idx(0), wpt(0), rdy(0), dskchg(0),
+		dir(0), stp(0), wtg(0), mon(0), ss(0), ds(-1), idx(0), wpt(1), rdy(0), dskchg(0),
 		ready(false),
 		rpm(0),
 		angular_speed(0),
@@ -340,7 +340,7 @@ void floppy_image_device::device_start()
 	actual_ss = 0;
 	ds = -1;
 	stp = 1;
-	wpt = 0;
+	wpt = 1;
 	dskchg = exists() ? 1 : 0;
 	index_timer = timer_alloc(0);
 	image_dirty = false;
@@ -438,10 +438,6 @@ void floppy_image_device::init_floppy_load(bool write_supported)
 
 	index_resync();
 
-	wpt = 1; // disk sleeve is covering the sensor
-	if (!cur_wpt_cb.isnull())
-		cur_wpt_cb(this, wpt);
-
 	wpt = is_readonly() || (!write_supported);
 	if (!cur_wpt_cb.isnull())
 		cur_wpt_cb(this, wpt);
@@ -508,11 +504,11 @@ void floppy_image_device::call_unload()
 		image.reset();
 	}
 
-	wpt = 1; // disk sleeve is covering the sensor
+	wpt = 0;
 	if (!cur_wpt_cb.isnull())
 		cur_wpt_cb(this, wpt);
 
-	wpt = 0; // sensor is uncovered
+	wpt = 1;
 	if (!cur_wpt_cb.isnull())
 		cur_wpt_cb(this, wpt);
 
@@ -2385,6 +2381,7 @@ void ibm_6360::setup_characteristics()
 mac_floppy_device::mac_floppy_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock) : floppy_image_device(mconfig, type, tag, owner, clock)
 {
 	m_has_mfm = false;
+	dskchg_writable = true;
 }
 
 void mac_floppy_device::device_start()
@@ -2422,7 +2419,7 @@ bool mac_floppy_device::wpt_r()
 	// actual_ss may have changed after the phases were set
 	m_reg = (m_reg & 7) | (actual_ss ? 8 : 0);
 
-	if(m_reg != 4 && m_reg != 12 && m_reg != 5 && m_reg != 13)
+	if(1 || (m_reg != 4 && m_reg != 12 && m_reg != 5 && m_reg != 13))
 		logerror("fdc disk sense reg %x %s %p\n", m_reg, regnames[m_reg], image.get());
 
 	switch(m_reg) {
@@ -2436,6 +2433,9 @@ bool mac_floppy_device::wpt_r()
 	case 0x2: // Is the motor on?
 		return mon;
 
+	case 0x3: // Disk change signal
+		return dskchg;
+
 	case 0x4:
 	case 0xc: // Index pulse, probably only on the superdrive though
 		return !m_has_mfm ? false : !image || mon ? true : idx;
@@ -2458,6 +2458,16 @@ bool mac_floppy_device::wpt_r()
 	case 0xa: // Not on track 0?
 		return cyl != 0;
 
+	case 0xb:{// Tachometer, 60 pulses/rotation
+		if(image.get() != nullptr && !mon) {
+			attotime base;
+			uint32_t pos = find_position(base, machine().time());
+			uint32_t subpos = pos % 3333334;
+			return subpos < 20000;
+		} else
+			return false;
+	}
+
 	case 0xd: // Is the current mode GCR or MFM?
 		return m_mfm;
 
@@ -2478,7 +2488,7 @@ void mac_floppy_device::seek_phase_w(int phases)
 		"DirNext", "StepOn", "MotorOn", "EjectOff",
 		"DirPrev", "StepOff", "MotorOff", "EjectOn",
 		"-", "MFMModeOn", "-", "-",
-		"-", "GCRModeOn", "-", "-"
+		"DskchgClear", "GCRModeOn", "-", "-"
 	};
 
 	bool prev_strb = m_strb;
@@ -2532,6 +2542,11 @@ void mac_floppy_device::seek_phase_w(int phases)
 			}
 			break;
 
+		case 0xc: // Clear dskchg
+			logerror("cmd clear dskchg\n");
+			dskchg = 0;
+			break;
+
 		case 0xd: // GCR mode on
 			logerror("cmd gcr on\n");
 			m_mfm = false;
diff --git a/src/devices/machine/iwm.cpp b/src/devices/machine/iwm.cpp
index d01640c16e8..5cb6490c970 100644
--- a/src/devices/machine/iwm.cpp
+++ b/src/devices/machine/iwm.cpp
@@ -250,7 +250,7 @@ u8 iwm_device::control(int offset, u8 data)
 
 	switch(m_control & 0xc0) {
 	case 0x00: return m_active ? m_data : 0xff;
-	case 0x40: return (m_status & 0x7f) | ((!m_floppy || m_floppy->wpt_r()) ? 0x80 : 0);;
+	case 0x40: return (m_status & 0x7f) | ((!m_floppy || m_floppy->wpt_r()) ? 0x80 : 0);
 	case 0x80: return m_whd;
 	case 0xc0: if(offset & 1) { if(m_active) data_w(data); else mode_w(data); } return 0xff;
 	}
@@ -382,8 +382,6 @@ void iwm_device::sync()
 				if(is_sync()) {
 					if(m_rsh >= 0x80) {
 						m_data = m_rsh;
-						if(m_data == 0xfc)
-							machine().debug_break();
 						m_rsh = 0;
 					} else if(m_rsh >= 0x04) {
 						m_data = m_rsh;
@@ -393,8 +391,7 @@ void iwm_device::sync()
 
 				} else if(m_rsh >= 0x80) {
 					m_data = m_rsh;
-					if(m_data == 0xfc)
-						machine().debug_break();
+					//					logerror("%s DATAR %02x\n", cycles_to_time(m_last_sync).to_string(), m_data);
 					m_rsh = 0;
 				}
 				break;